Recently, in German Offenlegungsschrift No. 2,165,651 a group of isoindole-1,3-diones which are useful as herbicides was disclosed. The general formula for the isoindole-1,3-diones disclosed in the Offenlegungsschrift is as follows: ##STR2## wherein R may be an aryl, aralkyl or benzyl optionally substituted with 1 to 5 halogen atoms, hydroxy, nitro, cyano, thiocyanato, carboxy, alkyl or halogenated alkyl, alkoxy, lower alkylthio, and phenyl groupings; a group having the configuration --O--CH.sub.2 A may also be substituted therein, wherein A is a phenyl or a naphthyl group, wherein the phenyl group may have one or more substituents therein, such as halogen atoms, nitro groupings, lower alkyl groupings or lower alkoxy groupings.
Typical of the compounds disclosed in the Offenlegungsschrift is the compound of Example 1: ##STR3##
Although the compounds disclosed within the Offenlegungsschrift are active herbicides, the need still exists for herbicides which are more active. The presence of undesired vegetation is very damaging to useful crops such as rice and wheat. In the current world situation, wherein food shortages are acute, it is most important not to lose a portion of a valuable crop such as rice or wheat. The presence of such undesired vegetation results in the loss of a significant portion of such crops. Thus, a need exists for a particularly effective herbicide which will destroy as much of this unwanted vegetation as is possible without causing significant damage to the desired crops, e.g. rice.
According to the instant invention, herbicidal compounds have been discovered which are highly active herbicides and yet cause minimal damage to certain desired crops, e.g. rice and wheat.